<!DOCTYPE html>
<html lang="en" xmlns:v-on="http://www.w3.org/1999/xhtml">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<div id="app">
    <button v-on:click="say">点击我</button>
</div>

<!--导入vue.js编写js代码-->
<script src="https://cdn.jsdelivr.net/npm/vue"></script>
<script>
    let vm = new Vue({
        el:"#app",
        data:{
            message: "Hello,Vue!"
        },
        methods:{
            say: function (event) {
                alert(this.message);
            }
        }
    });
</script>

</body>
</html>